[Python-Dev] Symbolic errno values in error messages
Hi, I spent some time googleing for "OSError 4" before it occurred to me that "4" was actually an irrelevant implementation detail. As soon as I searched for "EINTR", I found exactly what I was looking for. (not really but this is another story) I jumped to the conclusion that OSError.__str__() should return the symbolic error number instead of the integer value. I was about to write a patch but I just noticed that OSError and friends are implemented in C so I guess it will be a bit harder than expected. The error message comes from EnvironmentError.__str__() which is implemented by EnvironmentError_str() in Objects/exceptions.c. A Python implementation could have replaced self.errno in the format string args by errno.errorcode[self.errno]. However, it's not clear to me if there is such a mapping available in C. Since my fix is not as trivial as I expected, I ask for advice regarding the following questions: 1) Should OSError.__str__() print the symbolic name of errno? 2) Where can I find the symbolic name in C? Best regards, -- Yannick Gingras ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Symbolic errno values in error messages
"Alexander Belopolsky" <[EMAIL PROTECTED]> writes:
>>>> try:
> ...open('/')
> ... except Exception,e:
> ...pass
> ...
>>>> print e
> [Errno 21] Is a directory
>
> So now I am not sure what OP is proposing. Do you want to replace 21
> with EISDIR in the above?
Yes, that's what I had in mind.
--
Yannick Gingras
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Re: [Python-Dev] Symbolic errno values in error messages
"Alexandre Vassalotti" <[EMAIL PROTECTED]> writes:
>>> So now I am not sure what OP is proposing. Do you want to replace 21
>>> with EISDIR in the above?
>>
>> Yes, that's what I had in mind.
>>
>
> Then, check out EnvironmentError_str in Objects/exceptions.c. You
> should be able import the errno module and fetch its errorcode
> dictionary.
It wasn't as hard as I expected. It's the first time that I play with
the Python C API; I didn't expect the API to be that high level.
I attached a patch to convert errno to its symbolic value when an
EnvironmentError is printed. Should attach it to a ticket on
bugs.python.org?
I'm sure there is a style guide like PEP-8 for C code, feel free to
point me to it because my patch is probably not fully style compliant.
With Emacs, doing
M-x c-set-style python
doesn't seems to do the right thing. Are you all using a bunch of
shared settings in you .emacs files?
--
Yannick Gingras
Index: Objects/exceptions.c
===
--- Objects/exceptions.c (revision 63365)
+++ Objects/exceptions.c (working copy)
@@ -604,13 +604,32 @@
EnvironmentError_str(PyEnvironmentErrorObject *self)
{
PyObject *rtnval = NULL;
+PyObject *errnomod = NULL;
+PyObject *errorcode_dict = NULL;
+PyObject *errno_str = NULL;
+PyObject *printed_errno = NULL;
+/* Extract the symbolic value for errno.
+ Ex: use 'ENOTDIR' instead of 20 */
+if (self->myerrno) {
+errnomod = PyImport_ImportModule("errno");
+if (errnomod == NULL)
+ Py_FatalError("Can't import errno module.");
+
+ errorcode_dict = PyObject_GetAttrString(errnomod, "errorcode");
+ if (errorcode_dict == NULL)
+ Py_FatalError("Can't access errorcode dict.");
+
+ errno_str = PyDict_GetItem(errorcode_dict, self->myerrno);
+ printed_errno = errno_str ? errno_str : self->myerrno;
+}
+
if (self->filename) {
PyObject *fmt;
PyObject *repr;
PyObject *tuple;
-fmt = PyString_FromString("[Errno %s] %s: %s");
+fmt = PyString_FromString("[Errno=%s] %s: %s");
if (!fmt)
return NULL;
@@ -627,8 +646,8 @@
}
if (self->myerrno) {
-Py_INCREF(self->myerrno);
-PyTuple_SET_ITEM(tuple, 0, self->myerrno);
+Py_INCREF(printed_errno);
+PyTuple_SET_ITEM(tuple, 0, printed_errno);
}
else {
Py_INCREF(Py_None);
@@ -654,7 +673,7 @@
PyObject *fmt;
PyObject *tuple;
-fmt = PyString_FromString("[Errno %s] %s");
+fmt = PyString_FromString("[Errno=%s] %s");
if (!fmt)
return NULL;
@@ -665,8 +684,8 @@
}
if (self->myerrno) {
-Py_INCREF(self->myerrno);
-PyTuple_SET_ITEM(tuple, 0, self->myerrno);
+Py_INCREF(printed_errno);
+PyTuple_SET_ITEM(tuple, 0, printed_errno);
}
else {
Py_INCREF(Py_None);
@@ -688,7 +707,9 @@
}
else
rtnval = BaseException_str((PyBaseExceptionObject *)self);
-
+
+Py_XDECREF(errnomod);
+Py_XDECREF(errorcode_dict);
return rtnval;
}
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Re: [Python-Dev] Symbolic errno values in error messages
"Guido van Rossum" <[EMAIL PROTECTED]> writes: > Have you considered whether this works on all platforms? (E.g. > Windows, or embedded non-Unix-based.) Yes but I guess I didn't comment it properly. The line printed_errno = errno_str ? errno_str : self->myerrno; ensures that we gracefully fallback to numeric errno when here is no symbolic value available. The code is only invoked if there is an errno value, which takes care of most non-Unix platforms. -- Yannick Gingras ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
[Python-Dev] [patch] Duplicate sections detection in ConfigParser
Greetings Pythonistas,
ConfigParser as you most certainly know is a .ini parser included in
the Python standard library. It's documentation mentions a
DuplicateSectionError but I was puzzled after hunting a bug in our
application that this error was not raised when parsing a file with
duplicate sections. After looking at the code, it turns out that
DuplicateSectionError is only raised when using the builder interface;
the parser interface will never throw it.
The attached patch is compatible with both the 2.x and the 3.x
branches; it adds a `unique_sects` parameter to the constructor of
RawConfigParser and a test in the parser loop that raises
DuplicateSectionError if a section is seen more then once and that
unique_sects is True.
This is just a proof of concept and I'd like your opinion on it before
working on the final version. I see two main issues regarding
backward compatibility and uniformity. For uniformity `unique_sects`
should also apply to the builder interface. However, if it does, it
should default to True since it was the default behavior for the
builder interface to raise on duplicate sections. On the other hand,
the default behavior for the parser interface was to ignore duplicate
sections so making `unique_sects` default to True might break existing
code.
To summarize, I ask you all:
* Is the lack of duplicates detection in the parser a problem worth
addressing?
* Should `unique_sects` control the builder interface?
* Should it default to True?
Best regards,
--
Yannick Gingras
http://ygingras.net
Index: Lib/ConfigParser.py
===
--- Lib/ConfigParser.py (revision 68546)
+++ Lib/ConfigParser.py (working copy)
@@ -215,13 +215,14 @@
class RawConfigParser:
-def __init__(self, defaults=None, dict_type=dict):
+def __init__(self, defaults=None, dict_type=dict, unique_sects=False):
self._dict = dict_type
self._sections = self._dict()
self._defaults = self._dict()
if defaults:
for key, value in defaults.items():
self._defaults[self.optionxform(key)] = value
+self._unique_sects = unique_sects
def defaults(self):
return self._defaults
@@ -468,7 +469,10 @@
if mo:
sectname = mo.group('header')
if sectname in self._sections:
-cursect = self._sections[sectname]
+if self._unique_sects:
+raise DuplicateSectionError(sectname)
+else:
+cursect = self._sections[sectname]
elif sectname == DEFAULTSECT:
cursect = self._defaults
else:
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Re: [Python-Dev] [patch] Duplicate sections detection in ConfigParser
On Tuesday 03 February 2009, Raghuram Devarakonda wrote: > http://bugs.python.org/issue2204 refers to the same issue. Perhaps, > you can upload your patch there in addition to adding any comments. I attached the patch to the ticket. Do you have recommendations on how to solve the uniformity issue with the builder interface? -- Yannick Gingras http://ygingras.net signature.asc Description: This is a digitally signed message part. ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
